1. Field of the Invention
The present invention relates to an optical detector which is employed for an analyzer utilizing a capillary chromatography, and more particularly, it relates to an optical detector which is applied to a capillary electrophoresis apparatus, a liquid chromatography apparatus, or the like.
2. Description of the Background Art
It is preferable that the limit of detection of an analyzer, i.e., the signal-to-noise ratio of a detector, is as high as possible. In an optical detector, luminance of a light source is limited while samples or a capillary are deteriorated when light of excessive intensity is employed. Further, sensitivity of the detector also has a certain limit due to its detection principle.
When detection is performed in a photon count region in order to improve sensitivity, it takes so much time that no dynamic range can be obtained.
Thus, the signal-to-noise ratio of a detection system is inevitably limited even if the same is formed by an optimum light source, an optimum optical system and an optimum detector.